1. Field of the Invention
The present invention relates generally to a multiple channel wireless communication system, and more particularly, to an apparatus and method for dynamically allocating channels with different characteristics in a multiple channel wireless communication system.
2. Description of the Related Art
Research into a 4th Generation (4G) communication system, which is the next generation communication system, is currently being conducted to provide users with differing services having various Qualities of Service (QoSs) and supporting a data rate of about 100 Mbps. In particular, active research into the 4G communication system is being carried out to develop a new communication system guaranteeing mobility and QoS in order to support a high-speed service in a Broadband Wireless Access (BWA) communication system such as a wireless Local Area Network (LAN) system and a wireless Metropolitan Area Network (MAN) system. The Institute of Electrical and Electronics Engineers (IEEE) 802.16 communication system is a representative 4G communication system.
IEEE 802.16 communication systems support a diversity channel and a band Adaptive Modulation and Coding (AMC) channel. The diversity channel is a channel for preventing a degradation of reception performance of a specific terminal by distributing signals to be transmitted to the terminal, to any frequency band. The band AMC channel is a channel for increasing a usage efficiency of radio resources by allocating favorable frequency bands to terminals. In the diversity channel, a scheduling result is unimportant, because a signal is distributed to a random frequency band, whereas in the band AMC channel, a scheduling result greatly influences a reception performance of a corresponding terminal.
In general, the diversity channel and the band AMC channel are divided into time intervals. However, when a channel is divided into time intervals within one frame, the frame must be kept for more than a predetermined time length. That is, one frame should have a duration that is long enough to accommodate dividing the two channels by time. However, increasing the time length of one frame, increases the time interval for a base station to collect channel information with a terminal. This may cause a different channel state between a time point at which the base station collects the channel information and a time point at which the base station actually performs communication, thus resulting in a degradation of system performance. By contrast, if the time length of a frame gets shorter, a time difference between a time point at which a base station collects channel information and a time point at which the base station actually performs communication reduces, enabling an exact scheduling.
Therefore, a frame structure for achieving efficient channel division while reducing a frame length is needed. In other words, for implementing an efficient communication, a suitable distribution of the diversity channel and the band AMC channel within a frame, and an alternative for informing terminals of channel distribution are required.